Volcanoes destroy and volcanoes create. What is a Volcano? . Opening in the Earth’s surface where magma escapes The word volcano is derived from the name of Vulcano island off Sicily, which was named after Vulcan the Roman God of Fire . What is Volcanism?.
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Volcanismdescribes all the processes associated with the discharge of magma, hot fluids and gases
Commonly contains some crystals, fragments of surrounding (un-melted) rocks, and dissolved gases, but it is primarily a liquid composed principally of oxygen, silicon, aluminum, iron, magnesium, calcium, sodium, potassium, titanium, and manganese
Red hot when it pours or blasts out of a vent but soon changes to dark red, gray, black, or some other color as it cools and solidifies.
Very hot, gas-rich lava containing abundant iron and magnesium is fluid and flows like hot tar, whereas cooler, gas-poor lava high in silicon, sodium, and potassium flows sluggishly, like thick honey in some cases or in others like pasty, blocky masses
Played a key role in forming and modifying the planet
More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin
Courtesy of NASA
Oceanic-oceanic subduction zone
Produce a line of volcanoes parallel to the oceanic trench,
The chain of volcanoes is called an island arc
For Example theAleutian Island chain
Oceanic-continental subduction zone
Belt of volcanoes will be generated on continental crust
The belt is then called a volcanic arc
Characterized by explosive eruptions
For Example the U.S. Pacific northwest, and the Andes of South America and the most volcanically active belt on Earth is known as the Ring of Fire
Hot spots: Regions inside a plate with active volcanism
Unlike other volcanoes, not created at plate boundaries, created within the plate interiors
For Example The Hawaiian Islands